OpenGL Render restored.

I tried to make it integrate more with regular render but couldn't
do it well, it still needs a 3D view to take the settings from, and
can't run in a separate thread due to OpenGL.

However, it is now rendering to an offscreen buffer which then gets
displayed in the image window. This requires FBO's to be available, so
a fallback creating a new window is still needed. Currently available
from the Render menu in the top header.

3 files changed, 86 insertions, 1 deletions

diff --git a/source/blender/gpu/GPU_extensions.h b/source/blender/gpu/GPU_extensions.h
index a910ff9c3e7..c2af4e8fcb1 100644
--- a/source/blender/gpu/GPU_extensions.h
+++ b/source/blender/gpu/GPU_extensions.h
@@ -48,6 +48,9 @@ typedef struct GPUTexture GPUTexture;
 struct GPUFrameBuffer;
 typedef struct GPUFrameBuffer GPUFrameBuffer;
 
+struct GPUOffScreen;
+typedef struct GPUOffScreen GPUOffScreen;
+
 struct GPUShader;
 typedef struct GPUShader GPUShader;
 
@@ -107,6 +110,14 @@ void GPU_framebuffer_free(GPUFrameBuffer *fb);
 
 void GPU_framebuffer_restore();
 
+/* GPU OffScreen
+   - wrapper around framebuffer and texture for simple offscreen drawing */
+
+GPUOffScreen *GPU_offscreen_create(int width, int height);
+void GPU_offscreen_free(GPUOffScreen *ofs);
+void GPU_offscreen_bind(GPUOffScreen *ofs);
+void GPU_offscreen_unbind(GPUOffScreen *ofs);
+
 /* GPU Shader
    - only for fragment shaders now
    - must call texture bind before setting a texture as uniform! */
diff --git a/source/blender/gpu/intern/gpu_extensions.c b/source/blender/gpu/intern/gpu_extensions.c
index 5c8157be789..5deef4a5200 100644
--- a/source/blender/gpu/intern/gpu_extensions.c
+++ b/source/blender/gpu/intern/gpu_extensions.c
@@ -616,7 +616,7 @@ int GPU_framebuffer_texture_attach(GPUFrameBuffer *fb, GPUTexture *tex)
 	}
 	else {
 		glDrawBuffer(GL_COLOR_ATTACHMENT0_EXT);
-		glReadBuffer(GL_NONE);
+		glReadBuffer(GL_COLOR_ATTACHMENT0_EXT);
 	}
 
 	status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
@@ -727,6 +727,78 @@ void GPU_framebuffer_restore()
 	}
 }
 
+/* GPUOffScreen */
+
+struct GPUOffScreen {
+	GPUFrameBuffer *fb;
+	GPUTexture *color;
+	GPUTexture *depth;
+};
+
+GPUOffScreen *GPU_offscreen_create(int width, int height)
+{
+	GPUOffScreen *ofs;
+
+	ofs= MEM_callocN(sizeof(GPUOffScreen), "GPUOffScreen");
+
+	ofs->fb = GPU_framebuffer_create();
+	if(!ofs->fb) {
+		GPU_offscreen_free(ofs);
+		return NULL;
+	}
+
+	ofs->depth = GPU_texture_create_depth(width, height);
+	if(!ofs->depth) {
+		GPU_offscreen_free(ofs);
+		return NULL;
+	}
+
+	if(!GPU_framebuffer_texture_attach(ofs->fb, ofs->depth)) {
+		GPU_offscreen_free(ofs);
+		return NULL;
+	}
+
+	ofs->color = GPU_texture_create_2D(width, height, NULL);
+	if(!ofs->color) {
+		GPU_offscreen_free(ofs);
+		return NULL;
+	}
+
+	if(!GPU_framebuffer_texture_attach(ofs->fb, ofs->color)) {
+		GPU_offscreen_free(ofs);
+		return NULL;
+	}
+
+	GPU_framebuffer_restore();
+
+	return ofs;
+}
+
+void GPU_offscreen_free(GPUOffScreen *ofs)
+{
+	if(ofs->fb)
+		GPU_framebuffer_free(ofs->fb);
+	if(ofs->color)
+		GPU_texture_free(ofs->color);
+	if(ofs->depth)
+		GPU_texture_free(ofs->depth);
+	
+	MEM_freeN(ofs);
+}
+
+void GPU_offscreen_bind(GPUOffScreen *ofs)
+{
+	glDisable(GL_SCISSOR_TEST);
+	GPU_framebuffer_texture_bind(ofs->fb, ofs->color);
+}
+
+void GPU_offscreen_unbind(GPUOffScreen *ofs)
+{
+	GPU_framebuffer_texture_unbind(ofs->fb, ofs->color);
+	GPU_framebuffer_restore();
+	glEnable(GL_SCISSOR_TEST);
+}
+
 /* GPUShader */
 
 struct GPUShader {
diff --git a/source/blender/gpu/intern/gpu_material.c b/source/blender/gpu/intern/gpu_material.c
index 0dc17da93a1..0650a0bfa19 100644
--- a/source/blender/gpu/intern/gpu_material.c
+++ b/source/blender/gpu/intern/gpu_material.c
@@ -1509,6 +1509,7 @@ void GPU_lamp_shadow_buffer_bind(GPULamp *lamp, float viewmat[][4], int *winsize
 	Mat4MulMat4(lamp->persmat, persmat, rangemat);
 
 	/* opengl */
+	glDisable(GL_SCISSOR_TEST);
 	GPU_framebuffer_texture_bind(lamp->fb, lamp->tex);
 
 	/* set matrices */
@@ -1521,6 +1522,7 @@ void GPU_lamp_shadow_buffer_unbind(GPULamp *lamp)
 {
 	GPU_framebuffer_texture_unbind(lamp->fb, lamp->tex);
 	GPU_framebuffer_restore();
+	glEnable(GL_SCISSOR_TEST);
 }
 
 int GPU_lamp_shadow_layer(GPULamp *lamp)